Re: Species? was Re: Don't Constrain my Laws, Danny!

Danny Yee (danny@STAFF.CS.SU.OZ.AU)
Fri, 15 Sep 1995 10:48:09 +1000

> Maybe I am a bit obtuse Danny but if membership of a species is defined
> only by genealogy doesn't that make all animals (at least) members of the
> same species? Sure there must be something else involved to make species
> a meaningful concept.

"genealogy" was a bad word to use; it actually suggests an evolutionary
species approach. The BSC (biological species concept) stresses
reproductive isolation more. The following quote may be helpful.

A consensus appears to have been reached that species are
integrated unique entities. The so-called biological species
concept emphasizes that species are reproductive communities
within which genes are (or can be) freely exchanged, but
between which gene flow does not occur or at least is very
rare. ...

The evolutionary species concept is an important extension
of the concept of biological species, an attempt to broaden
the definition to include all sorts of organisms (not just
sexually reproductive ones) and to portray the existence
of species through time. According to this view species
are separate ancestor-descendant lineages with their own
evolutionary roles, tendencies, and fates. ...

Ghiselin (1974) and Hull (1976, 1978) have examined the status
of species from a philosophical standpoint. They contend that
if species are to play the role required of them in current
systematic and evolutionary theory, they must be "individuals"
(i.e., integrated and cohesive entities with a restricted
spatiotemporal location) rather than "classes" (i.e.,
spatiotemporally unbounded sets with defining characteristics).

>From Mishler and Donoghue, _Systematic Zoology_, 1982, 31: 491-503,
reprinted in in Sober, _Conceptual Issues in Biology_, the MIT Press 1994.

I notice that Hull (1978), reprinted in the same volume, even mentions
anthropology. Here's the abstract:

Biological species have been treated traditionally as
spatiotemporally unrestricted classes. If they are to perform
the function which they do in the evolutionary process, they
must be spatiotemporally localized individuals, historical
entities. Reinterpreting biological species as historical
entities solves several important anomalies in biology,
in philosophy of biology, and within philosophy itself.
It also has important implications for any attempt to present
an "evolutionary" analysis of science and for sciences such
as anthropology which are devoted to the study of a single

Danny Yee.